[sarex] ISS simplex M

MM ka1rrw at yahoo.com
Sat Aug 12 06:29:16 PDT 2006

The big problem is Not the Voice Split frequency on
It is the IARU regional restrictions placed on ISS

ITU passes laws!
ITU says Satellite is ok 144.000- 146.000
IARU does not pass Laws.
IARU said ISS must follow IARU region plans.
(And there are also Local Country law too)

Before I go any further, I would like the thank the
ARISS team, including Frank Bauer for working very had
with the IARU in getting ISS some assigned
frequencies.  I know first hand how difficult it is to
negotiate with 180+ counties to get them to agree on a
frequency plan.  Frank went to the IARU and came back
with some frequencies several years ago.  It may not
have been exactly what we wanted, but it was a
starting point.  And now we had some Assigned
frequencies to work with. Let’s use them and find out
what works, and what needs to be changed.  Then
document the issues, collect reports from all of the
ISS crews and see if we need to go back to the IARU
and ask for some changes.

The ISS is the first Amateur Satellite to ever have an
IARU regional restriction.
The two different voice channels based on Regions were
an experiment.
Guess what, the experiment failed.  We can now learn
from this experiment.

As the Space Station Mir Sysop for 10 years, I was
directly involved in many Frequency negotiations.  At
the First ARISS meeting November 1996, a proposal was
present to put Mir on 145.800 down and 145.200 up. 
The Experiment ran from Mid November 1996 until mid
February 1997.  The Mir crew was very helpful in
reporting the QRM levels, etc.  The Frequency 145.200
could not be used worldwide; it was just too busy. 
The Mir crew switched back to 145.985 and stayed there
until Mission end in 2001.  With the Mir station we
had an advantage that ISS did not have.  We had access
to a crew that knew the importance of Amateur Radio
and were willing to experiment with any frequency we
gave them to find a clear channel.  On ISS we just do
not have that luxury with ISS.  All of our QRM
estimates have to be based on local terrestrial

The ISS crew is programmed to follow Order, Rules and
The ISS crew knows they have to change channels
depending on which IARU region they are over. The ISS
crew does not know when they are near an IARU border.

Countries need to do a better job at sharing Weak
Signal portions of the Band.
Mir got kicked off 145.550 simplex because some people
in the UK did not want to share the simplex band with
MIR Space Station.  We were only in range of the UK
for a maximum of 1 hour per day.  Fortunately I had
been previously experimented with frequencies from
Mir, So I put Mir on 145.895 and no one complained.

ARISS needs to interview all of the ISS ham crews and
ask them some simple questions.
Would a worldwide voice channel help you with your
voice contacts?
Would you have used the radio more often if you had a
worldwide voice channel?

ISS Satellite operators need to talk to their IARU
representatives and present their case.  
We need a worldwide Voice Channel for the ISS crews on
2-meters.  And maybe more for the Commercial Space
Station later this decade and for the Moon Landes
Repeaters too.

Sharing of Frequencies:
It is possible for some types of Weak Signal
operations to share a band Segment.
Example: If you asked 100 2-meter weak signal beacon
listening operators, “would you mind sharing the band
with the International Space Station for a maximum of
1 hour per day”
I will guess and say that most friendly hams would not
mind “Sharing” our limited resources with another weak
signal mode.

There are some modes that you can not share with,
because of their duty cycle and bandwidth
requirements. During the Mir program we discovered
that FM repeater outputs and Packet BBS’s are modes
you must stay very far away from.  Our calculations
indicate the absolute minimum frequency separation
between a weak satellite Signal and a FM repeater
output is 25 kHz.  (Assuming the FM Repeater
transmitter is at least 40 kilometers away).

So lets collect data from the ISS crew.

Document the data

Present the data to the IARU along with the input from
the Amateur Radio satellite community.

And solve the problem.

Just a suggestion.


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